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At least 19 recordsLinked to original sources
USGS1973

Atlas of Mars, Amenthes quadrangle, MC-14

This mosaic is made with computer enhanced Mariner 9 pictures, rectified and scaled to a Mercator projection. Computer processing was performed by the Image Processing Laboratory (IPL) of the Jet Propulsion Laboratory (JPL). Processing included contrast enhancement and high-pass filtering which accentuates topographic features while subduing albedo variations. Photographic reproductions of the images were generated from the IPL digital magnetic tapes and mosaicked by the U.S. Geological Survey. Relative horizontal placement of pictures is controlled by spacecraft tracking data, with adjustment to fit the Mariner 9 control net of August, 1972 (Davies, M.E., 1972, Mariner 9 control net of Mars: August, 1972: Rand Corp., R-1122-JPL) where possible. Individual analytical adjustment of pictures was not performed. Triangles are shown at the correct latitude and longitude of the control points identified and numbered by Davies (ibid.). Broken crosses are used to identify the images of the control points. Standard deviation of image placement discrepancy is less than 5 km. The-projection is based on a theoretical dynamical ellipticity of 1/192. The scale is based on an equatorial radius of 3393.4 km.

Open-File Report↗
USGS1973

Atlas of Mars, Memnonia quadrangle, MC-16

This mosaic was made with Mariner 9 pictures provided by the Jet Propulsion Laboratory (JPL), California Institute of Technology. The Image Processing Laboratory (IPL) of JPL processed the digital pictures to remove image artifacts and geometric distortions, to enhance high-frequency topographic detail while subduing low-frequency albedo variation, and to transform the pictures to a Mercator projection. The U.S. Geological Survey performed further artifact removal and modified contrast and tone of each picture analytically on the digital magnetic tapes provided by IPL for uniformity of tone and contrast within the mosaic. Photographic reproductions of the pictures were generated from the magnetic tapes and mosaicked by the U. S. Geological Survey. Primary horizontal control points, where available, controlled the placement of pictures. Where these points were not available, picture placement was controlled by spacecraft tracking data and by matching images in overlap zones between pictures. Discrepancies in matching these images are less than 10 km over 90% of the mosaic. The number designations and positions of the primary control points, shown by broken crosses (-l-), are those given by Davies and Arthur (1973). Aerographic latitudes are shown on this mosaic. The projection is based on a theoretical dynamical ellipticity of 1/192. The scale is based on an equatorial radius of 3393. 4 km.

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